The mission was named after and headed by Iwakura Tomomi in the role of extraordinary and plenipotentiary ambassador, assisted by four vice-ambassadors, three of which (Okubo Toshimichi, Kido Takayoshi, and Ito Hirobumi) were also ministers in the Japanese government. The historian Kume Kunitake was the official diarist, keeping a detailed log of all events and impressions. Also included were a number of administrators and scholars, totalling 48 people.

In addition to the mission staff, about 60 students were brought along. Several of them were left behind to complete educations in the foreign countries, including five young women who stayed in U.S.A. to study, among them the then 7-year old Tsuda Umeko who after returning to Japan founded (in 1900) the renowned school now called the Tsuda College.

Kaneko Kentaro was left in the U.S.A. too as a student and later met Theodore Roosevelt in university. They became friends and their relationship resulted later in Roosevelt's mediation at the end of Russo-Japanese war and the Treaty of Portsmouth.

Nakae Chomin, who was a member of the mission staff and the Ministry of Justice, stayed in France to study the French legal system. Later he became a journalist, thinker and translator and introduced French thinkers like Jean-Jacques Rousseau into Japan.

On December 23, 1871 the mission sailed from Yokohama, bound for San Franscisco. From there it continued to Washington, D.C., then to Britain, France, Belgium, the Netherlands, Russia, Prussia, Germany, Denmark, Sweden, Austria, Italy, and Switzerland. On the return journey, Egypt, Aden, Ceylon, Singapore, Saigon, Hong Kong, and Shanghai were also visited, although much more briefly. The mission returned home September 13, 1873, almost two years after setting out.